Metal complex compounds

ABSTRACT

A monocyclopentadienyl or substituted monocyclopentadienyl metal complex containing compound useful as a polymerization catalyst corresponding to the formula: 
     
       
         CpMX n   + A −   
       
     
     wherein: 
     Cp is an η 5 -substituted cyclopentadienyl group optionally covalently bonded to M through a substituent, said Cp being substituted in at least one occurrence with an alkoxy or aryloxy group; 
     M is a metal of Group 3-10 or the Lanthanide Series of the Periodic Table bound in an ηhu 5 bonding mode to the cyclopentadienyl or substituted cyclopentadienyl group; 
     X each occurrence independently is selected from the group consisting of hydride, halo, alkyl, aryl, silyl, germyl, aryloxy, alkoxy, amide, siloxy, neutral Lewis base ligands and combinations thereof having up to 20 non-hydrogen atoms, and optionally one X together with Cp forms a metallocycle with M; 
     R is alkyl or aryl of up to 10 carbons; 
     n is one or two depending on the valence of M; and 
     A is a noncoordinating, compatible anion of a Bronsted acid salt.

CROSS-REFERENCE TO RELATED APPLICATION

This is a Continuation of application Ser. No. 07/834,435, filed Feb.12, 1992, now abandoned, which is a continuation of application Ser. No.07/758,654, filed Sep. 12, 1991, now U.S. Pat. No. 5,132,380, issuedJul. 21, 1992, which is a divisional of Ser. No. 07/547,728, filed Jul.3, 1990, now U.S. Pat. No. 5,064,802, issued Nov. 12, 1991, which is acontinuation-in-part of Ser. No. 07/407,169, filed Sep. 14, 1989, nowabandoned. The teachings of the foregoing applications are hereinincorporated by reference.

BACKGROUND OF THE INVENTION

This invention relates to compositions of matter which are useful ascatalysts, to a method for preparing these catalysts and to a method ofusing these catalysts. More particularly, this invention relates tocatalyst compositions, to a method of preparing these catalystcompositions, to a method for polymerizing addition polymerizablemonomers using the present catalysts.

In U.S. Ser. No. 8,800, filed Jan. 30, 1987 and now abandoned (publishedin equivalent form as EP 277,004) there are disclosed certainbis(cyclopentadienyl) metal compounds formed by reacting abis(cyclopentadienyl) metal complex with salts of Bronsted acidscontaining a non-coordinating compatible anion. The reference disclosesthe fact that such complexes are usefully employed as catalysts in thepolymerization of olefins. For the teachings contained herein theaforementioned U.S. Ser. No. 8,800 (now abandoned) and EP 277,004 areherein incorporated in their entirety by reference thereto.

Despite the utility of the catalysts disclosed in the above prior artreferences it is desirable to produce even more efficient and usefulcatalysts for addition polymerizations. In particular the presentinvestigations have led to certain improved metal complex containingcompounds that are highly active as polymerization catalysts anddesirably allow for the polymerization of a wide variety of monomers andmixtures of monomers.

SUMMARY OF THE INVENTION

According to the present invention there is now provided amonocyclopentadienyl or substituted monocyclopentadienyl metal complexcontaining compound useful as an olefin polymerization catalystcorresponding to the formula:

CpMX_(n) ⁺A⁻

wherein:

Cp is a single η⁵-cyclopentadienyl or η⁵-substituted cyclopentadienylgroup optionally covalently bonded to M through a substituent;

M is a metal of Group 3-10 or the Lanthanide Series of the PeriodicTable bound in an η⁵ bonding mode to the cyclopentadienyl or substitutedcyclopentadienyl group;

X each occurrence independently is selected from the group consisting ofhydride, halo, alkyl, aryl, silyl, germyl, aryloxy, alkoxy, amide,siloxy, neutral Lewis base ligands and combinations thereof having up to20 non-hydrogen atoms, and optionally one X together with Cp forms ametallocycle with M;

n is one or two depending on the valence of M; and

A⁻ is a noncoordinating, compatible anion of a Bronsted acid salt.

Such compounds are usefully employed in Ziegler-Natta typepolymerization processes to prepare polymers for molding, film, sheet,extrusion foaming and other applications. The compounds may also beutilized in hydrogenation reactions, catalytic cracking and otherindustrial processes.

DETAILED DESCRIPTION OF THE INVENTION

The compounds of the present invention are prepared by combining:

a) at least one first component which is a mono(cyclopentadienyl)derivative of a metal of Group 3-10 or the Lanthanide Series of thePeriodic Table of the Elements containing at least one substituent whichwill combine with the cation of a second component (describedhereinafter) which first component is capable or forming a cationformally having a coordination number that is one less than its valence,

b) and at least one second component which is a salt of a Bronsted acidand a noncoordinating, compatible anion.

More particularly the noncoordinating, compatible anion of the Bronstedacid salt may comprise a single coordination complex comprising acharge-bearing metal or metalloid core, which anion is both bulky andnon-nucleophilic. The recitation “metalloid”, as used herein, includesnon-metals such as boron, phosphorus and the like which exhibitsemi-metallic characteristics.

All reference to the Periodic Table of the Elements herein shall referto the Periodic Table of the Elements, published and copyrighted by CRCPress, Inc., 1989. Also, any reference to a Group or Groups shall be tothe Group or Groups as reflected in this Periodic Table of the Elementsusing the IUPAC system for numbering groups.

As used herein, the recitation “noncoordinating, compatible anion” meansan anion which either does not coordinate to the monocyclopentadienyl orsubstituted monocyclopentadienyl group containing cation or which isonly weakly coordinated to said cation thereby remaining sufficientlylabile to be displaced by a neutral Lewis base. A noncoordinating,compatible anion specifically refers to a compatible anion which whenfunctioning as a charge balancing anion in the catalyst system of thisinvention does not transfer an anionic substituent or fragment thereofto said cation thereby forming a neural four coordinate metallocene anda neutral metal or metalloid byproduct. “Compatible anions” are anionswhich are not degraded to neutrality when the initially formed complexdecomposes and are noninterfering with desired subsequent polymerizationor other uses of the complex.

Monocyclopentadienyl and substituted monocyclopentadienyl groups for useaccording to the present invention are more specifically depicted by theformula:

wherein:

R′ each occurrence is independently selected from the group consistingof hydrogen, halogen, alkyl, aryl, haloalkyl, alkoxy, aryloxy, and silylgroups of up to 20 non-hydrogen atoms, or two or more R′ groups togethermay form a fused ring system; and

R″ individually may be R′ or a group that is covalently bonded to M ofthe formula: —Z—Y—, wherein

Z is a divalent moiety comprising oxygen, boron, or a member of group 14of the periodic table of the elements; and

Y is a linking group covalently bonded to the metal comprising nitrogen,phosphorus, oxygen or sulfur, or optionally Z and Y together form afused ring system.

In a highly preferred embodiment R″ is

wherein:

E independently each occurrence is carbon, silicon, or germanium;

p is an integer from 1 to 4;

Y is nitrogen or phosphorous; and

R′″ independently each occurrence is alkyl, aryl, silyl or combinationsthereof having up to 10 carbon or silicon atoms.

Thus highly preferred compositions according to the invention correspondto the formula:

wherein:

M is zirconium or titanium;

Cp* is a cyclopentadienyl or substituted cyclopentadienyl group bound inan η⁵ bonding mode to M;

Z is SiR*₂, CR*₂, SiR*₂SiR*₂, CR*₂CR*₂, CR*═CR*, CR*₂SiR *₂, or GeR*₂;wherein:

R each occurrence is independently selected from the group consisting ofhydrogen, alkyl, aryl, silyl, halogenated alkyl, halogenated aryl groupshaving up to 20 non-hydrogen atoms, and mixtures thereof, or two or moreR* groups form a fused ring system,

Y is a nitrogen or phosphorus containing group corresponding to theformula —N(R″″)— or —P(R″″)—, wherein R″″ is C₁₋₁₀ alkyl or aryl, ie. anamido or phosphido group;

X is independently each occurrence halo, alkyl, aryl, alkoxy, or aryloxyof up to 20 carbons;

n is one or two; and

A⁻ is a noncoordinating, compatible anion of a Bronsted acid salt.

Illustrative, but not limiting examples of monocyclopentadienyl metalcomponents (first components) which may be used in the preparation ofthe compounds of this invention are derivatives of titanium, zirconium,hafnium, chromium, lanthanum, etc. Preferred components are titanium orzirconium compounds. Examples of suitable monocyclopentadienyl metalcompounds are hydrocarbyl-substituted monocyclopentadienyl metalcompounds such as cyclopentadienylzirconium trimethyl,cyclopentadienylzirconium triethyl, cyclopentadienylzirconium tripropyl,cyclopentadienyltitanium trimethyl, cyclopentadienyltitanium triphenyl,cyclopentadienyl-scandium bis(p-tolyl), cyclopentadienylchromium2,4-pentadienyl, pentamethyloyclopentadienylyltriumbis(bistrimethylsilylmethyl), pentamethylcyclo-pentadienylscandiumbis(bistrimethylsilylmethyl), pentamethylcyclopentadienyllanthanumbis(bistrimethyl-silylmethyl), etc.; hydrocarbyloxy substitutedcompounds such as cyclopentadienyltitanium triisopropoxide,cyclopentadienylzirconium triphenoxide, etc.; halo substituted compoundssuch as cyclopentadienylzirconium trichloride, indenyltitaniumtrichloride, pentamethylcyclopentadienylhafnium trichloride,cyclopentadienylyitrium dichloride, etc.; and compounds comprisingmixtures of substituents such as cyclopentadienyltitanium isopropoxidedimethyl, pentamethyloyclopentadienylzirconium methyl dichloride,cyclopentadienyllanthanum chloro isopropoxide,(tert-butylamido)(tetramethyl-η⁵-cyclopentadienyl)-1,2-ethanediylzirconiumdichloride,(tert-butylamido)(tetra-methyl-η⁵-cyclopentadienyl)-1,2-ethanediyltitaniumdichloride,(methylamido)(tetramethyl-η⁵-cyclopentadienyl)-1,2-ethanediylzirconiumdichloride,(methylamido)(tetramethyl-η⁵-cyclopentadienyl)-1,2ethanediyltitaniumdichloride,(ethylamido)(tetramethyl-η⁵-cyclopentadienyl)-methylenetitaniumdichloro, (tert-butylamido)dibenzyl(tetramethyl-η⁵-cyclopentadienyl)-silanezirconium dibenzyl,(benzylamido)dimethyl-(tetramethyl-η⁵-cyclopentadienyl)silanetitaniumdichloride,(phenylphosphido)dimethyl(tetramethyl-η⁵-cyclopentadienyl)silanezirconiumdibenzyl, and the like.

The last enumerated compounds of the above list is illustrative ofcompounds containing covalent bonds between the metal atom andsubstituents of the cyclopentadienyl ring. Preferred substituents arethose which are capable of σ-bonding to the metal atom. Such componentsare readily prepared by combining the corresponding metal chloride witha dilithium salt of the substituted cyclopentadienyl group such as acyclopentadienyl-alkanediyl, cyclopentadienyl—silane amide, orcyclopentadienyl—phosphide compound. The reaction is conducted in aninert liquid such as tetrahydrofuran, C₅₋₁₀ alkanes, toluene, etc.utilizing conventional synthetic procedures. Certain of these compoundsare further disclosed and claimed in the recently filed U.S. patentapplication, Ser. No. 401,344, filed Aug. 31, 1989 and assigned to thesame assignee as the present invention, which teachings are incorporatedherein in their entirety by reference thereto.

Compounds useful as a second component in the preparation of thecompounds of this invention will comprise a cation, which is a Bronstedacid capable of donating a proton, and a compatible noncoordinatinganion. Preferred anions are those containing a single coordinationcomplex comprising a charge-bearing metal or metalloid core which anionis relatively large (bulky), capable of stabilizing the active catalystspecies (the Group 3-10 or Lanthanide Series cation) which is formedwhen the two components are combined and said anion will be sufficientlylabile to be displaced by olefinic, diolefinic and acetylenicallyunsaturated substrates or other neutral Lewis bases such as ethers,nitrites and the like. Suitable metals, then, include, but are notlimited to, aluminum, gold, platinum and the like. Suitable metalloidsinclude, but are not limited to, boron, phosphorus, silicon and thelike. Compounds containing anions which comprise coordination complexescontaining a single metal or metalloid atom are, of course, well knownand many, particularly such compounds containing a single boron atom inthe anion portion, are available commercially. In light of this, saltscontaining anions comprising a coordination complex containing a singleboron atom are preferred.

Preferably the second component useful in the preparation of thecatalysts of this invention may be represented by the following generalformula:

wherein:

L is a neutral Lewis base;

(L−H)⁺ is a Bronsted acid; and

is a compatible, noncoordinating anion.

More preferably [A]^(d−) corresponds to the formula:

[M′^(m +)Q_(n)]^(d−)

wherein:

m is an integer from 1 to 7;

n is an integer from 2 to 8;

n−m=d;

M′ is a metal or metalloid selected from Groups 5-15 of the PeriodicTable of the Elements; and

Q independently each occurrence is selected from the Group consisting ofhydride, dialkylamido, halide, alkoxide, aryloxide, hydrocarbyl, andsubstituted-hydrocarbyl radicals of up to 20 carbons with the provisothat in not more than one occurrence is Q halide.

Second components comprising boron which are particularly useful in thepreparation of catalysts of this invention may be represented by thefollowing general formula:

[L−H]⁺[BQ₄]⁻

wherein:

L is a neutral Lewis base;

[L−H]⁺ is a Bronsted acid;

B is boron in a valence state of 3; and

Q is as previously defined.

Illustrative, but not limiting, examples of boron compounds which may beused as a second component in the preparation of the improved catalystsof this invention are trialkyl-substituted ammonium salts such astriethylammonium tetraphenylborate, tripropylammonium tetraphenylborate,tri(n-butyl)ammonium tetraphenylborate, trimethylammoniumtetra(p-tolylborate), tributylammonium tetrakis-pentafluorophenylborate,tripropylammonium tetrakis-2,4-dimethylphenylborate, tributylammoniumtetrakis-3,5-dimethylphenylborate, triethylammoniumtetrakis-(3,5-di-trifluoromethyl-phenyl)borate and the like. Alsosuitable are N,N-dialkyl anilinium salts such as N,N-dimethyl-aniliniumtetraphenylborate, N,N-diethylanilinium tetraphenylborate,N,N-2,4,6-pentamethylanilinium tetraphenylborate and the like; dialkylammonium salts such as di-(i-propyl)ammoniumtetrakis-pentafluorophenylborate, dicyclohexylammoniumtetra-phenylborate and the like; and triaryl phosphonium salts such astriphenylphosphonium tetraphenylborate, tri(methylphenyl)phosphoniumtetrakis-pentafluorophenyl-borate, tri(dimethylphenyl)phosphoniumtetraphenylborate and the like.

Similar lists of suitable compounds containing other metals andmetalloids which are useful as second components could be made, but suchlists are not deemed necessary to a complete disclosure. In this regard,it should be noted that the foregoing lists is not intended to beexhaustive and other boron compounds that would be useful as well asuseful components containing other metals or metalloids would be readilyapparent from the foregoing general formula and examples to thoseskilled in the art.

In general, and while most first components identified above may becombined with most second components identified above to produce anactive olefin polymerization catalyst, it is important to continuedpolymerization operations that either the metal cation initially formedfrom the first component or a decomposition product thereof be arelatively stable catalyst. It is also important that the anion of thesecond compound be stable to hydrolysis when an ammonium salt is used.Further, it is important that the acidity of the second component besufficient, relative to the first, to facilitate the needed protontransfer. Conversely, the basicity of the metal complex must also besufficient to facilitate the needed proton transfer. Certain metallocenecompounds are resistant to reaction with all but the strongest Bronstedacids and thus are not suitable as first components to form thecatalysts of this invention with all second components. Most preferredmonocyclopentadienyl metal compounds are those which can be hydrolyzedby aqueous solutions.

With respect to the combination of first (metal containing) component tosecond component to form a catalyst of this invention, it should benoted that the two components that are combined for preparation of theactive catalyst must be selected so as to avoid transfer of a fragmentof the anion, particularly an aryl group, or a fluorine or hydrogen atomto the metal cation, thereby forming a catalytically inactive species.This could be done by steric hinderance, resulting from substitutions onthe cyclopentadienyl carbon atoms as well as substitutions on thearomatic carbon atoms of the anion. It follows, then, that firstcomponents comprising perhydrocarbyl-substituted cyclopentadienylradicals could be effectively used with a broader range of secondcompounds than could first components comprising unsubstitutedcyclopentadienyl radicals. As the amount and size of the substitutionson the cyclopentadienyl radicals are reduced, however, more effectivecatalysts are obtained with second compounds containing anions which aremore resistant to degradation, such as those with substituents on theortho positions of the phenyl rings. Another means of rendering theanion more resistant to degradation is afforded by fluorinesubstitution, especially perfluoro-substitution, in the anion.Fluoro-substituted stabilizing anions may, then, be used with a broaderrange of first components.

In general, the catalyst can be prepared by combining the two componentsin a suitable solvent at a temperature within the range from about −100°C. to about 300° C. The catalyst may be used to polymerize α-olefinsand/or acetylenically unsaturated monomers having from 2 to about 18carbon atoms and/or diolefins having from 4 to about 18 carbon atomseither alone or in combination. The catalyst may also be used topolymerize α-olefins, diolefins an/or acetylenically unsaturatedmonomers in combination with other unsaturated monomers. In a preferredembodiment the catalysts are employed to prepare copolymers of mixturesof vinyl aromatic monomers with olefins other than a vinyl aromaticmonomer, specifically copolymers of styrene with ethylene or propylene.In general, the polymerization may be accomplished at conditions wellknown in the prior art. It will, of course, be appreciated that thecatalyst system will form insitu if the components thereof are addeddirectly to the polymerization process and a suitable solvent ordiluent, including condensed monomer, is used in said polymerizationprocess. It is, however, preferred to form the catalyst in a separatestep in a suitable solvent prior to adding the same to thepolymerization step. While the catalysts may not contain pyrophoricspecies, the catalysts' components are sensitive to both moisture andoxygen and should be handled and transferred in an inert atmosphere suchas nitrogen, argon or helium.

As indicated supra, the improved catalyst of the present invention will,preferably, be prepared in a suitable solvent or diluent. Suitablesolvents or diluents include any of the solvents known in the prior artto be useful as solvents in the polymerization of olefins, diolefins andacetylenically unsaturated monomers. Suitable solvents, then, include,but are not necessarily limited to, straight and branched-chainhydrocarbons such as isobutane, butane, pentane, hexane, heptane, octaneand the like; cyclic and alicyclic hydrocarbons such cyclohexane,cycloheptane, methylcyclohexane, methylcycloheptane and the like andaromatic and alkyl-substituted aromatic compounds such as benzene,toluene, xylene and the like. Suitable solvents also include liquidolefins which may act as monomers or comonomers including ethylene,propylene, butadiene, cyclopentene, 1-hexene, 3-methyl-1-pentene,4-methyl-1-pentene, 1,4-hexadiene, 1-octene, 1-decene, styrene, and thelike.

While the inventors do not wish to be bound by any particular theory, itis believed that when the two components used to prepare the improvedcatalysts of the present invention are combined in a suitable solvent ordiluent, all or part of the cation of the second component (the acidicproton) combines with one of the substituents (X) on the firstcomponent. As a result a neutral compound, XH is liberated, whichneutral compound either remains in solution or is liberated as a gas. Inthis regard, it should be noted that if X in the first component ishydride, hydrogen gas may be liberated. Similarly, if X is a methylradical, methane may be liberated as a gas. If X is alkoxide an alcoholresults, etc.

While still not wishing to be bound by any particular theory, it is alsobelieved that as one of the first component substituents is liberated,the noncoordinating anion originally contained in the second componentused in the catalyst preparation balances the charge of either the metalcation formed from the first component, or a decomposition productthereof. The metal cation and noncoordinating anion will remain socombined until the catalyst is contacted with one or more olefins,diolefins and/or acetylenically unsaturated monomers either alone or incombination with one or more other monomers or another neutral Lewisbase. As indicated supra, the anion contained in the second compoundmust be sufficiently labile to permit rapid displacement by an monomerto facilitate polymerization.

The chemical reactions which occur in forming the catalysts of thisinvention may, when a preferred, boron containing compound is used asthe second component, be represented by reference to the general formulaset forth herein as follows:

CpMX_(n+1)+[L−H]⁺[BQ₄]⁻→[CpMX_(n)]⁺[BQ₄]⁻+X−H+L

wherein Cp, M, X, n and Q have the previously identified meanings.

In general the stability and rate of formation of the products in theforegoing reaction equations, particularly the metal cation, will varydepending upon the choice of the solvent, the acidity of the [L−H]⁺selected, the particular L, the anion, the temperature at which thereaction is completed and the particular monocyclopentadienyl derivativeof the metal selected. Generally, the initially formed ion-pair will bean active polymerization catalyst and will polymerize α-olefins,diolefins and acetylenically unsaturated monomers either alone or incombination with other monomers. In some cases, however, the initialmetal cation will decompose to yield an active polymerization catalyst.

As indicated supra, most first compounds identified above will combinewith most second compounds identified above to produce an activecatalyst, particularly an active polymerization catalyst. The actualactive catalyst species is not, however, always sufficiently stable asto permit its separation and subsequent identification. Moreover, andwhile many of the initial metal cations formed are relatively stable, ithas become apparent that the initially formed metal cation frequentlydecomposes into one or more other catalytically active species.

In general, catalysts according to the present invention can be selectedso as to produce polymer products that will be free of certain tracemetals generally found in polymers produced with Ziegler-Natta typecatalysts containing cocatalysts such as aluminum or magnesium basedcompounds. The polymer products produced with the catalyst of thisinvention should, then, have a broader range of applications thanpolymers produced with more conventional Ziegler-Natta type catalystscomprising a metal alkyl, such as an aluminum alkyl, or an aluminoxane.The catalysts may be employed as homogeneous catalysts or supported onthe surface of a suitable support such as alumina or silica.

In a most preferred embodiment of the present invention Cp ispentamethyloyclopentadiene, M is titanium or zirconium, n is two, X isC₁₋₄ alkyl or alkoxide, and A⁻ is tetrakis-pentafluorophenyl borate.

In a further preferred embodiment, the catalyst is used to polymerize alower α-olefin, particularly ethylene or propylene, most preferablyethylene, at a temperature within the range from 0° C. to 200° C.,preferably 25° C. to 100° C. and at a pressure within the range fromatmospheric to 6,894 kPa (1000 psig) preferably 100 kPa to 3,400 kPa (15to 500 psig). In a most preferred embodiment of the present invention,the catalyst will be used either to homopolymerize ethylene or tocopolymerize ethylene with a lower α-olefin having from 3 to 8 carbonatoms (including styrene) thereby yielding a plastic or an elastomericcopolymer. In both the preferred and most preferred embodiments, themonomers will be maintained at polymerization conditions for a nominalholding time within the range from about 1 to about 60 minutes and thecatalyst will be used at a concentration within the range from about10⁻⁷ to about 10⁻¹ moles per mole of monomer.

Having thus broadly described the present invention it is believed thatthe same will become even more apparent by reference to the followingexamples. It will be appreciated, however, that the examples arepresented solely for the purpose of illustration and should not beconstrued as limiting the invention.

EXAMPLE 1

In a drybox, at room temperature, 33 mg ofpentamethylcyclopentadienyltitaniumisopropoxide dimethyl(CpTi(0-i-Pr)Me₂) (0.12 mmoles) was combined with 1 mL of benzene andthe resultant solution was pipetted into a 250 mL 3-necked flask. Astopper, an adapter for the vacuum line, and a solid addition funnelwere attached. The addition funnel was charged with 80 mg (0.10 mmoles)of triethylammonium tetrakis-pentafluorophenylborate([HNEt₃]⁺[B(C₆F₅)₄]⁻). The addition funnel was stoppered and theapparatus was attached to a vacuum line. The benzene was removed fromthe flask under vacuum, and 75 mL of fresh benzene was distilled intothe flask at −78° C. under vacuum. After warming to room temperature,the solution was blanketed with 1 atmosphere of ethylene. The solid([HNEt₃]⁺[B(C₆F₅)₄]⁻ was added at room temperature and the solution wasobserved to turn yellow. After 20 minutes the solution was black and aprecipitate of polyethylene was observed. After one hour, the polymerwas precipitated with methanol, collected, washed with methanol anddried in a vacuum oven overnight to yield 0.49 g of polymer.

EXAMPLE 2

The reaction conditions of Example 1 were substantially repeatedutilizing pentamethylcyclopentadienyl titanium trimethyl andtriethylammonium tetrakis-pentafluorophenyl borate. The reaction wasconducted in toluene at room temperature for ˜10 hrs. Methane gas andammonia byproducts were observed. After heating to ˜45° C. for one hourthe toluene solvent was removed under vacuum leaving a black solid. Thesolid was washed three times with petroleum ether and dried underreduced pressure. The recovered product was identified as the desiredpentamethylcyclopentadienyl-titanium dimethyl tetrakis-pentafluorophenylborate which may be employed to polymerize an olefin monomer under knownZiegler-Natta polymerization conditions.

What is claimed is:
 1. A monocyclopentadienyl metal complex containingcompound useful as an olefin polymerization corresponding to theformula: CpMX_(n) ⁺ A⁻, wherein: Cp is a single cyclopentadienyl groupsubstituted with at least one alkoxy or aryloxy group of up to 20non-hydrogen atoms; M is titanium; X each occurrence is independentlyselected from the group consisting of hydride, halo, alkyl, aryl, silyl,germyl, aryloxy, alkoxy, amide, siloxy, and combinations thereof havingup to 20 non-hydrogen atoms; n is one or two depending on the valence ofM; and A⁻ is a noncoordinating, compatible anion of a Bronsted acidsalt.
 2. A compound according to claim 1 wherein n is
 2. 3. Asubstituted monocyclopentadienyl metal complex containing compoundcorresponding to the formula: CpMX_(n) ⁺A⁻, where Cp is of the formula:

wherein: R′ each occurrence is independently selected from the groupconsisting of hydrogen, halogen, alkyl, aryl, haloalkyl, alkoxy,aryloxy, and silyl groups, said R′ having up to 20 non-hydrogen atoms,or two or more R′ groups together may form a fused ring system, with theproviso that in at least one occurrence R′ is alkoxy or aryloxy; M istitanium; X is independently each occurrence halo, alkyl, aryl, NR₂,aryloxy or alkoxy, said X having up to 20 carbons; R is alkyl or aryl,said R having up to 10 carbons; n is one, and A⁻ is a noncoordinating,compatible anion of a Bronsted acid salt.
 4. A compound according toclaim 3 wherein A⁻ is BQ₄ ⁻, wherein: B is boron in a valence state of3; and Q independently each occurrence is selected from the groupconsisting of hydride, dialkylamido, halide, alkoxide, aryloxide,hydrcarbyl and fluoro-substituted hydrocarbyl radicals, said Q having upto 20 carbons, with the proviso that in not more than one occurrence isQ halide.
 5. A compound according to claim 3 wherein A⁻ istetrakis(pentafluoro-phenyl)borate.
 6. A compound according to any oneof claims 1-5, wherein X each occurrence is C₁₋₄ alkyl.
 7. A compoundaccording to claim 6 wherein X each occurrence is methyl.
 8. A processfor preparing a metal complex according to claim 1, the steps of theprocess comprising: a) contacting a first component corresponding to theformula: CpMX_(n+1), with a second component corresponding to theformula [L−H]⁺[A]⁻, wherein L is a neutral Lewis base and Cp, M, X, n,and A⁻ are as previously defined in claim 1, and b) recovering theresulting product.
 9. A process according to claim 8 wherein the secondcomponent corresponds to the formula [L−H]⁺[BQ₄]⁻ wherein L is a neutralLewis base and Q independently each occurrence is selected from thegroups consisting of hydride, dialkylamido, halide, hydrocarbyl,substituted hydrocarbyl and organometalloid of up to 20 carbons, withthe proviso that in not more than one occurrence is Q halide.
 10. Aprocess according to claim 9 wherein Q is pentafluorophenyl.
 11. Aprocess according to any one of claims 8-10 wherein X each occurrence isC₁₋₄ alkyl.
 12. A process according to claim 11 wherein X eachoccurrence is methyl.
 13. A monocyclopentadienyl metal complexcontaining compound corresponding to the formula:

wherein: M is titanium; Cp* is a substituted cyclopentadienyl groupbound in an η⁵ bonding mode to M and substituted with at least onealkoxy or aryloxy group of up to 20 non-hydrogen atoms; Z is SiR*₂,CR*₂, SiR*₂SiR₂, CR*₂CR*₂, CR*═CR*, CR*₂SiR*₂, or GeR*₂; wherein: R*each occurrence is independently selected from the group consisting ofhydrogen, alkyl, aryl, silyl, halogenated alkyl, halogenated aryl groupshaving up to 20 non-hydrogen atoms, and mixtures thereof, or two or moreR* groups form a fused ring system; Y is a nitrogen or phosphoruscontaining group corresponding to the formula —N(R″″)— or —P(R″″)—,wherein R′″ is t-butyl benzyl or aryl; X is independently eachoccurrence halo, alkyl, aryl, alkoxy, or aryloxy of up to 20 carbons; nis one; and A⁻ is a non-coordinating, compatible anion of a Bronstedacid salt.
 14. A compound according to claim 13 wherein A⁻ istetrakis(pentafluorophenyl)borate.
 15. A compound according to claim 13or 14 wherein X is C₁₋₄ alkyl.
 16. A compound according to claim 15wherein X is methyl.
 17. A substituted monocyclopentadienyl derivativeof titanium, prepared by combining a first component corresponding tothe formula: CpMX_(n+1), where CpM is of the formula:

wherein: R′ each occurrence is independently selected from the groupconsisting of hydrogen, halogen, alkyl, aryl, alkoxy, aryloxy andhaloalkyl groups, said R′ having up to 20 non-hydrogen atoms, or two ormore R′ groups together may form a fused ring system, with the provisothat in at least one occurrence R′ is alkoxy or aryloxy; M is titanium;Y is nitrogen or phosphorus; R′″ independently each occurrence ist-butyl, benzyl, aryl, silyl or combinations thereof, said groups havingup to 10 carbon or silicon atoms; X is independently each occurrencehalo, alkyl, aryl, NR₂, aryloxy or alkoxy, said X having up to 20carbons; R is alkyl or aryl, said R having up to 10 carbons; and n isone, with a second component which is a salt of a Bronsted acid and anoncoordinating, compatible anion.
 18. A derivative according to claim17 wherein the second component corresponds to the formula:(L−H)⁺(BQ₄)⁻, wherein L is a neutral Lewis base; B is boron in a valencestate of 3; and Q independently each occurrence is selected from thegroup consisting of hydride, dialkylamido, halide, alkoxide, aryloxide,hydrocarbyl, and fluoro-substituted hydrocarbyl radicals, said Q havingup to 20 carbons, with the proviso that in not more than one occurrenceis Q halide.
 19. A derivative according to claim 18 wherein Qindependently each occurrence is a perfluoro-substituted hydrocarbylradical of up to 20 carbons.
 20. A derivative according to claim 19wherein (BQ4)⁻ is tetrakis-pentafluorophenyl borate.
 21. A derivativeaccording to any one of claims 17-20 wherein the second component is atrialkyl-substituted ammonium salt.
 22. A derivative according to claim21 wherein the second component is triethylammoniumtetrakispentafluorophenylborate.
 23. A derivative according to any oneof claims 17-22 wherein X each occurrence is C₁₋₄ alkyl.
 24. Aderivative according to claim 23 wherein X each occurrence is methyl.25. A process for preparing a monocyclopentadienyl derivative oftitanium comprising combining a first component corresponding to theformula: CpMX_(n+1), where CpM is of the formula:

wherein: R′ each occurrence is independently selected from the groupconsisting of hydrogen, halogen, alkyl, aryl, alkoxy, aryloxy andhaloalkyl groups, said R′ having up to 20 non-hydrogen atoms, or two ormore R′ groups together may form a fused ring system, with the provisothat in at least one occurrence R′ is alkoxy or aryloxy; M is titanium;Y is nitrogen or phosphorus; R′″ independently each occurrence ist-butyl, benzyl, aryl, silyl or combinations thereof, said R′″ having upto 10 carbon or silicon atoms; X is independently each occurrence halo,alkyl, aryl, NR₂, aryloxy or alkoxy, said X having up to 20 carbons; Ris alkyl or aryl, said R having up to 10 carbons; and n is one, with asecond component which is a salt of a Bronsted acid and anoncoordinating, compatible anion, and recovering the resulting product.26. A process according to claim 25 wherein the second componentcorresponds to the formula: (L−H)⁺(BQ₄)⁻, wherein L is a neutral Lewisbase; B is boron in a valence state of 3; and Q independently eachoccurrence is selected from the group consisting of hydride,dialkylamido, halide, alkoxide, aryloxide, hydrocarbyl, andfluoro-substituted hydrocarbyl radicals, said Q having up to 20 carbons,with the proviso that in not more than one occurrence is Q halide.
 27. Aprocess according to claim 26 wherein Q independently each occurrence isa perfluoro-substituted hydrocarbyl radical of up to 20 carbons.
 28. Aprocess according to claim 26 wherein (BQ₄)⁻ istetrakis-pentafluorophenyl borate.
 29. A process according to any one ofclaims 25-28 wherein the second component is a trialkyl-substitutedammonium salt.
 30. A process according to claim 25 wherein the secondcomponent is triethylammonium tetrakispentafluorophenyl borate.
 31. Aprocess according to any one of claims 25-33 wherein X each occurrenceis C₁₋₄ alkyl.
 32. A process according to claim 31 wherein X eachoccurrence is methyl.
 33. A substituted monocyclopentadienyl metalcomplex containing compound corresponding to the formula: CpMX_(n) ⁺A⁻,where Cp is of the formula:

wherein: R′ each occurrence is independently selected from the groupconsisting of hydrogen, halogen, alkyl, aryl, alkoxy, aryloxy andhaloalkyl groups, said R′ having up to 20 non-hydrogen atoms, or two ormore R′ groups together may form a fused ring system, with the provisothat in at least one occurrence R′ is alkoxy or aryloxy; and R″ is agroup that is covalently bonded to M of the formula: —Z—Y—, wherein: Zis a divalent moiety comprising oxygen, boron, or a member of Group 14of the Periodic Table of the elements; and Y is a linking groupcovalently bonded to the metal comprising phosphorus, oxygen or sulfur,or optionally Z and Y together form a fused ring system; M is titanium;X is independently each occurrence halo, alkyl, aryl, NR₂, aryloxy oralkoxy, said X having up to 20 carbons; R is alkyl or aryl, said Rhaving up to 10 carbons; n is one, and A⁻ is a noncoordinating,compatible anion of a Bronsted acid salt.
 34. A compound according toclaim 33 wherein R″ is

wherein: E independently each occurrence is carbon, silicon, orgermanium; p is an integer from 1 to 4; Y′ is phosphorus; and R′″independently each occurrence is alkyl, aryl, silyl or a combinationthereof, said R′″ having up to 10 carbon or silicon atoms.
 35. Acompound according to claim 33 wherein Z is SiR′″₂, where R′″independently each occurrence is alkyl, aryl, silyl or a combinationthereof, said R′″ having up to 10 carbon or silicon atoms.
 36. Acompound according to any one of claims 33-35 wherein A⁻ is BQ₄ ⁻wherein: B is boron in a valence state of 3; and Q independently eachoccurrence is selected from the group consisting of hydride,dialkylamido, halide, alkoxide, aryloxide, hydrocarbyl, andfluoro-substituted hydrocarbyl radicals, said Q having up to 20 carbons,with the proviso that in not more than one occurrence is Q halide.
 37. Acompound according to claim 36 wherein A⁻ istetrakis(pentafluorophenyl)borate.
 38. A compound according to claim 36wherein X each occurrence is C₁₋₄ alkyl.
 39. A compound according toclaim 38 wherein X each occurrence is methyl.
 40. A compound accordingto claim 37 wherein X each occurrence is C₁₋₄ alkyl.
 41. A compoundaccording to claim 40 wherein X each occurrence is methyl.
 42. Asubstituted monocyclopentadienyl metal complex containing compoundcorresponding to the formula: CpMX_(n) ⁺A⁻, where Cp is of the formula:

wherein: R′ each occurrence is independently selected from the groupconsisting of hydrogen, halogen, alkyl, aryl, haloalkyl, alkoxy,aryloxy, and silyl groups of up to 20 non-hydrogen atoms, or two or moreR′ groups together may form a fused ring system, with the proviso thatin at least one occurrence R′ is aryloxy; and R″ is a group that iscovalently bonded to M of the formula: —Z—Y—, wherein: Z is a divalentmoiety comprising oxygen, boron, or a member of Group 14 of the PeriodicTable of the elements; and Y is a linking group covalently bonded to themetal comprising nitrogen, phosphorus, oxygen or sulfur, or optionally Zan Y together form a fused ring system; M is titanium; X isindependently each occurrence halo, alkyl, aryl, NR₂, aryloxy or alkoxy,said X having up to 20 carbons; R is alkyl or aryl, said R having up to10 carbons; n is one, and A⁻ is a noncoordinating, compatible anion of aBronsted acid salt.
 43. A compound according to claim 42 wherein R″ is

wherein: E independently each occurrence is carbon, silicon, orgermanium; p is an integer from 1 to 4; Y is nitrogen or phosphorus; andR′″ independently each occurrence is alkyl, aryl, silyl or a combinationthereof, said R′″ having up to 10 carbon or silicon atoms.
 44. Acompound according to claim 43 wherein Z is SiR′″₂, where R′″independently each occurrence is alkyl, aryl, silyl or a combinationthereof, said R′″ having up to 10 carbon or silicon atoms.
 45. Acompound according to any one of claims 42-44 wherein A⁻ is BQ₄ ⁻wherein: B is boron in a valence state of 3; and Q independently eachoccurrence is selected from the group consisting of hydride,dialkylamido, halide, alkoxide, aryloxide, hydrocarbyl, andfluoro-substituted hydrocarbyl radicals, said Q having up to 20 carbons,with the proviso that in not more than one occurrence is Q halide.
 46. Acompound according to claim 45 wherein A⁻ istetrakis(pentafluorophenyl)borate.
 47. A compound according to any oneof claims 42-45 wherein X each occurrence is C₁₋₄ alkyl.
 48. A compoundaccording to claim 47 wherein X each occurrence is methyl.
 49. Acompound according to claim 46 wherein X each occurrence is C₁₋₄ alkyl.50. A compound according to claim 49 wherein X each occurrence ismethyl.